California Agency Proposes Stricter Goal For Hexavalent Chromium in Drinking Water

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LOS ANGELES--California's Office of Environmental Health Hazard Assessment on Dec. 31 proposed a level of hexavalent chromium in drinking water of 0.02 part per billion as a health protection goal.

The recommendation came in a draft technical document that updated the agency's August 2009 proposal suggesting the safe level for the chemical at 0.06 ppb (161 DEN A-4, 8/24/09).

The August 2009 proposal was never made final. OEHHA's newly proposed public health goal comes as environmental groups pressure the U.S. Environmental Protection Agency to establish a strict standard for hexavalent chromium in drinking water (244 DEN A-5, 12/22/10.

The California Department of Public Health will use the public health goal to establish a maximum contaminant level for hexavalent chromium. Under state law, the standard must be set as close to the public health goal as is economically and technically feasible.

First State to Set Limit on Pollutant

“When finalized, the public health goal will give California a solid scientific basis for a health-protective drinking water standard for chromium 6,’’ OEHHA Director Joan Denton said in a statement announcing the new proposal. “We expected the goal will be the first in the nation for this contaminant.”

State law currently limits total chromium in drinking water to 50 ppb, compared to EPA's 100 ppb standard for total chromium.

Newly available research suggests that young children and other vulnerable populations are more susceptible than the general population to exposure to carcinogens, OEHHA said.

An independent scientific panel that reviewed the technical document recommended a tighter public health goal, OEHHA said. The 0.02 ppb level also reflects OEHHA's new guidelines for early-in-life exposures, the agency said.

The proposed public health goal translates to a cancer risk rate to humans of one case per million, meaning that for every million people who drink tap water containing 0.02 ppb of hexavalent chromium daily for 70 years, there would be one additional cancer case due to the exposure.

OEHHA will accept written comments on its latest proposal until the close of business Jan. 31.

Hexavalent Chromium Use

Hexavalent chromium is used in a variety of industrial operations, including metal alloy processing, plating, leather tanning, and textile manufacturing. It also occurs naturally, but typically is converted into trivalent chromium, a less harmful metal, in plants and animals and humans.

Use of the chemical has tainted groundwater supplies throughout California. In 2010, the Department of Public Health reported that 2,208 sources of drinking water statewide had hexavalent chromium levels of 1 ppb or higher.

In its revised proposal OEHHA said recent studies indicate oral exposure to hexavalent chromium may cause cancer in humans.

By Carolyn Whetzel  


OEHHA's revised “Draft Public Health Goal for Hexavalent Chromium in Drinking Water” is available at http://www.oehha.ca.gov/water/phg/pdf/123110Chrom6.pdf.

Information on submitting comments on the document is available at

http://www.oehha.ca.gov/water/phg/chrom123110.html.